Unfortunately, nobody can really answer your question. In my experience as both a teacher and a language learner, pronunciation mistakes cause problems that are completely unpredictable. Sometimes, I am sure that I have mispronounced a word here in China, but people understand me. Other times, I think I pronounce something correctly, but people are confused.

One thing I have noticed is that misunderstandings can increase when vocabulary and sentence structure are weak. A good, clear sentence using the appropriate vocabulary can help overcome poor pronunciation while short, limited sentences made up of vague words makes a pronunciation mistake a major problem.

Another thing I have noticed, at least for English, is that rhythm is very important. Of course, you must pronounce each sound as clearly as possible (Some of my weaker students in China leave out many sounds when they speak. For example, they might pronounce television as "elewiya"!) but as long as you come close, and have good rhythm, you can usually be understood.

But I think it's important to watch out and correct mistake in the classroom sesion. We all know nobody speaks perfect; however when some one teaches should be aware that students make progress in their learning process

What I want to say is that in daily life, a mispronunciation doesn't matter as long as people can understand you. But, a mispronunciation in classroom should be corredted immediately because that may affect students' learning.

I venture to state that a given context allows a specific error margin. Foreign language learners are usually given a wider berth for phonetic, lexical, and grammatical mistakes, but native speakers find no such compassion: speech pathologists tend to earn an incredible amount of money helping a wide array of speakers overcome their specific phonetic difficulties.

In a formal business context, phonetic errors would be detrimental but pale in comparison with cultural blunders.